Safety signal operator



Feb. 20, 1940. E. E. HANSON 2,191,381

SAFETY SIGNAL OPERATOR Filed April '7, 1939 Patented Feb. 20, 1940 UNITED STATES PATENT OFFICE 2 Claims.

This invention relates to signal operators and more particularly to a circuit closing device connected to a hydraulic brake system for actuating a signal upon reduction of pressure in the system through breakage or leakage in the fluid system.

An object of this invention is to provide a safety device in the form of a pressure operated circuit closing member which under normal pressure in the fluid system of a hydraulic brake system is adapted to be maintained in a circuit opening position but which upon reduction of pressure in the system below normal pressure through leakage in the system is adapted to be moved to a circuit closing position for operating a remotely disposed signal.

A further object of this invention is to provide an automatic circuit closing means which is adapted to be interposed in a hydraulic brake system which may be readily adjusted to effect closing of the signal circuit at a predetermined reduction of pressure in the hydraulic brake system.

To the foregoing objects and to others which may hereinafter appear, the invention consists of the novel construction, combination and arrangement of parts as will be more specifically referred to and illustrated in the accompanying drawing, wherein an embodiment of the inven tion is shown, but it is to be understood that changes, variations and modifications may be resorted to which fall within the scope of the invention as claimed.

In the drawing:

Figure 1 is a diagrammatic view of a hydraulic brake system having a circuit closing means constructed according to an embodiment of this invention connected thereto,

Figure 2 is a sectional view taken on the line 22 of Figure 3,

Figure 3 is a sectional view taken on the line 3-3 of Figure 2, and

Figure 4 is a perspective view of the flexible diaphragm used with the signal operator.

Referring to the drawing, the numeral I i designates generally a pressure member which is connected to a pipe II and which is operated by means of a connecting rod [2. The connecting rod 12 is connected to a pedal or rockable operator 13 so that rocking of the operator 13 will effect movement of the piston rod [2 and thereby force liquid from the pump or pressure member Ill into the pipe line H. The pipe line H is connected to a longitudinally extending pipe line H which is connected to a transverse line l5 atone end of the vehicle and is also connected to a second transverse pipe line H5 at the opposite end of the vehicle. The pipe lines I5 and I6 are adapted to be connected to brake operators (not shown) and which are of conventional construction.

In order to provide a means whereby the operator of the vehicle may readily determine when a break has occurred in the pipe lines II, l4, l5 or 16, I have provided a signal operating member comprising a housing generally designated as ll. Th housing ll comprises a cup-shaped member [8 having a cylindrical bore l9 and a threaded reduced bore communicating with the bore IS. The bore 20 is adapted to be connected by means of a pipe 2| and a connector 22 to the hydraulic system between the pressure member l0 and the brake operators and in the present instance, the pipe 2! is connected to the pipe H.

A cylinder He provided with a flange 23 is secured to the head or cupshaped member 18 by means of bolts 24 and in the present instance, the flange 23 has a seat 25 within which the cap or head member 18 engages. In this manner the head or cap it is adapted to be maintained in axial relation to the cylinder 22a. The cylinder 22a. is provided with a bore 26 within which a piston 27 is slidable. The piston 21 at the inner end thereof is provided with a flange 28 which is engageable in an annular seat 29 provided in the inner end of the cylinder 22a. The flange 28 acts as a means to limit the movement of the piston 21 inwardly of the cylinder or bore 26.

The cylinder 22a is provided with a reduced extension 29 having a bore 30 which communicates at its inner end with the cylinder or bore 26. A spring 3! is loosely mounted in the bore 3!! and at its outer end engages against a plate 32 having a stud 33 integral therewith and about which the outer end of the spring engages so as to hold the spring 3! centrally of the bore 30. The plate 32 is provided with a tapered recess 34 on the outer face thereof within which the inner end of a threaded adjusting member 35 is adapted to engage. The adjusting member 35 is threaded through an opening 36 in the extension 29 and is locked in adjusted position by a lock nut 31.

The piston 27 at its outer end is provided with a recess 38 within which the inner end of the spring 3| engages. The piston 2'! is also provided at a point between the ends thereof with an annular groove or channel 39 and a contact member 40 is threaded through an insulating i; it

end oi the block or body 4! which is fastened to the housing ll by means of a bolt or screw 42. The cylinder 2a is provided with a relatively large opening at through which the terminal or contact member loosely engages so that the inner endof the contact or terminal member 49 will be insulated from the housing or cylinder 22a. The inner end of the contact member 40 loosely engages in the groove 39 and when the piston 2"! is at the end of its outward movement with the pressure normal in the fluid system, the inner end of the contact or terminal 40 will be spaced from the adjacent side walls of the groove 39. However, when a leakage occurs in the hydraulic braking system, the spring 3! which is tensioned by the tensionable screw 35 will move the piston 27 inwardly until the outer Wall of the groove 39 contacts with the pin or terminal member it].

A flexible diaphragm in the form of a yieldable cup M is positioned in the bore itand the diamember M is adapted to be flexed by e of the fluid from the pipe line 25 so as to normally hold the piston 2'! in a circuit opening position. The head 65 of the diaph agm M adapted to engage against the head or flange of the piston illand the diaphragm or piston operator provided with an annular flange d6 engaging in the bore iii. The flange it is provided with an annular groove ll between the ends. thereof and also with longitudinally extending communicating with the groove ll anu with the forward face of the head 4.5 so that in the event any liquid leaks past the diaphragm 1 {it this liquid may be forced rearwardly through the grooves 33 and the groove 2 terminal or contact member 48 is adapted to be connected by means of a conductor M to one side of a signal 5i! which may be a visible signal in the form of a light bulb or may be an audible rent supply 52 is grounded to the hydraulic systorn by r 1. of a conductor which is connected to the frame of the machine or to one of the .ipes forming the hydraulic brake system. In present instance, the conductor 53 is con d to the pipe In the use -nd operation of this safety signal operator, the housing i! is adapted to be connected between the pressure member and the brake operators by means or" the pipe 2 l. The terminal ll? is connected to a signal iiil by a con-- ductor it and under normal. pressure in the hydraulic system the pressure of the liquid will exthe d hragm #15 so as to maintain the piston if? in its outermost position against the tension the spring 3!. In this position. the inner terminal 3-9 will be positioned interide walls of the groove and also bottom wall of the groove 39 so that the electric circuit comprising the pipe lines and the conductors 35i, and [it will be open. However, in

the event the pressure in the braking system between. the pressure member H: and the brake operators drops below a predetermined normal pressure, the spring 3i will move the piston 21 inwardly until the inner end of the terminal 4!] contacts with the outer wall of the groove 39.

in this position the circuit to the signal member 58 will be closed so that the operator of the vehicle will be able to readily determine that a leakage or abnormal reduction of pressure in the braking system has occurred. The adjustment of the screw 35 will regulate the tension on the spring 3i so as to thereby effect an inward movement of the piston 21 at a predetermined reduction in pressure within the hydraulic braking system.

A signal operator constructed according to this invention can be readily interposed in a conventional hydraulic braking system without changing the present parts of the braking system, it only being necessary to connect the housing or signal operating member ii to a selected point within the braking system. The particular point of the position of the signal operator i! may be at any convenient point within the system wherein the pressure of the liquid is affected by the operation of the pressure member it.

What I claim is: g

1. In a hydraulic braking system, a safety signal operating means comprising a housing adapted to be connected to the braking system, a piston slidable in said housing, a diaphragm in said housing confronting one end of said piston and adapted to be flexed by pressure in said system, tensionable means in said housing engaging the opposite end of said piston, said piston having an annular groove therein and said housing having an opening confronting said groove, a terminal loosely engaging through said opening and projecting into said groove and normally spaced from, the walls of said groove, insulated means fixed to said housing supporting said terminal relative to said housing, said housing having an annular seat therein adjacent said one end of said piston, and an annular flange carried by said one end of said piston engageable with said seat to thereby limit the movement on one direction of said piston under inward flexing of said diaphragm.

2. In a hydraulic braking system, a safety signal. operating means comprising a housing adapted to be connected to the braking system, a piston slidable in said housing, diaphragm in said housing confronting one end of said piston and adapted to be flexed inwardly against said piston to thereby move said piston in onedireotion by pressure of liquid in said system, a spring in said housing engaging the opposite end of said piston and normally urging said piston in the opposite direction, threaded tens-ionable means for said spring, said piston having an annular groove between the ends thereof, saidhousing having an opening confronting said groove, a terminal extending loosely through said opening and loosely engaging in said groove, an insulated member fixed to said housing and supporting said terminal, said housing having an annular seat therein adjacent said one end of said piston, and an annular flange carried by said piston engageable on said seat to thereby limit the movement of said piston in said one direction by said diaphragm, the tension of said spr ng being such that upon reduction of liquid pressure against said diaphragm said. spring will move said piston in the opposite direction to thereby effect contact of said terminal with a wall of said groove and thereby effect a closing of an electrical circuit.

ERNEST E. HANSON. 

